Polyurethanes with reduced aldehyde emission

Abstract

The present invention relates to a process for the production of polyurethanes where (a) polyisocyanate, (b) polymeric compounds having groups reactive toward isocyanates, (c) catalysts, (d) polymer P formed from ethylenically unsaturated monomers and having an average of more than 2 functional groups of the formula —O—NH2 and optionally (e) blowing agent, (f) chain extender and/or crosslinking agent, and (g) auxiliaries and/or additives are mixed to give a reaction mixture, and the reaction mixture is allowed to complete a reaction to give the polyurethane. The present invention further relates to polyurethanes produced by this process and to the use of these polyurethanes in the interior of means of transport.

The invention claimed is: 
     
       1. A process for the production of polyurethanes, the process comprising:
 mixing 
 (a) polyisocyanate, 
 (b) polymeric compounds having groups reactive toward isocyanates, 
 (c) catalysts, and 
 (d) polymer P formed from ethylenically unsaturated monomers and having an average of more than 2 functional groups of the formula —O—NH 2    
 to give a reaction mixture, and allowing the reaction mixture to complete a reaction to give the polyurethane. 
 
     
     
       2. The process according to  claim 1 , wherein the polymer P is a homo- or copolymer having an average of more than 2 repeat units M A  derived from a monoethylenically unsaturated monomer A bearing a functional group of the formula —O—NH 2 . 
     
     
       3. The process according to  claim 1 , wherein the monoethylenically unsaturated monomer A has the formula I: 
       
         
           
           
               
               
           
         
         in which 
         R is hydrogen or methyl; and 
         A is a group of the formula X—[O-Alk] n  in which X is a chemical bond or is a bivalent radical which is bonded to the carbon atom that bears R and is selected from phenylene, phenylene-CH 2 —, C(O), CH 2 , O—C 2 -C 12 -alkanediyl and C(O)—NR c —(C 2 -C 10 -alkanediyl) where R c  is hydrogen, C 1 -C 4 -alkyl or —(C 2 -C 12 -alkanediyl)-O—NH 2 , 
         n is a number from 0 to 20, where n is not 0 when X is C(O), and 
         Alk is C 2 -C 4 -alkanediyl. 
       
     
     
       4. The process according to  claim 3 , wherein R is hydrogen and A is phenylene-CH 2 . 
     
     
       5. The process according to  claim 1 , wherein the polymer P is a copolymer having, aside from the repeat units of the formula M A , at least one further repeat unit M B  derived from monoethylenically unsaturated monomers B having no functional group of the formula —O—NR 1 R 2 . 
     
     
       6. The process according to  claim 5 , wherein the monomers B comprise monomers B1 selected from the group consisting of monoethylenically unsaturated C 3 -C 8 -monocarboxylic acids, monoethylenically unsaturated C 3 -C 8 -monocarboxylic acids, monoethylenically unsaturated sulfonic acids, amides of monoethylenically unsaturated C 3 -C 8 -monocarboxylic acids, hydroxy-C 2 -C 4 -alkyl esters of monoethylenically unsaturated C 3 -C 8 -monocarboxylic acids, poly-C 2 -C 4 -alkylene oxide esters of monoethylenically unsaturated C 3 -C 8 -monocarboxylic acids, di-C 1 -C 4 -alkylamino-C 2 -C 4 -alkyl esters of monoethylenically unsaturated C 3 -C 8 -monocarboxylic acids and N-vinyl lactams. 
     
     
       7. The process according to  claim 5 , wherein the molar ratio of repeat units M A  to repeat units M B  is in the range from 1:100 to 10:1. 
     
     
       8. The process according to  claim 6 , wherein the molar proportion of the monomers B1, based on the total number of monomers B, is 10 to 100 mol %. 
     
     
       9. The process according to  claim 1 , wherein the polymer P is in dissolved form in the aqueous composition. 
     
     
       10. The process as claimed in  claim 1  wherein the mixing step comprises further mixing
 (e) a blowing agent, 
 (f) at least one of a chain extender and a crosslinking agent, and 
 (g) at least one auxiliary or additive 
 to give the reaction mixture. 
 
     
     
       11. The process as claimed in  claim 1 , wherein the polymeric compounds (b) having groups reactive toward isocyanates comprise polyetherols. 
     
     
       12. The process as claimed  claim 1 , wherein the catalysts (c) comprise incorporable amine catalysts. 
     
     
       13. The process as claimed in  claim 12 , wherein compounds used as incorporable catalysts have, alongside the group(s) reactive toward isocyanates, at least one tertiary aliphatic amino group. 
     
     
       14. The process as claimed in  claim 1 , wherein the polyurethane is a polyurethane foam with an average density of from 20 to 850 g/L. 
     
     
       15. The process as claimed in  claim 1 , wherein the polyurethane is a compact polyurethane with an average density of more than 850 g/L. 
     
     
       16. A polyurethane produced by a process as claimed in  claim 1 . 
     
     
       17. A method of using the polyurethanes as claimed in  claim 16 , the method comprising molding said polyurethanes in the preparation of interiors in means of transport. 
     
     
       18. The process as claimed in  claim 10 , wherein the quantity comprised of component (d), based on the total weight of components (a) to (f), is from 0.01 to 2% by weight. 
     
     
       19. The method of  claim 17  wherein the polyurethane as claimed in  claim 16  is molded to form at least one of carpet-backing foam, acoustic foam, door cladding, roof lining, a steering wheel, a control knob, a seat cushion, door side backing, an instrument panel, a headrest, and cable sheathing used in the interior of the means of transport.